1 Overview

Sample selection protocol:

  1. Stationary trips

  2. Complete checklists (report all species)

  3. Drop duplicates from group trips.

  4. Drop trips with 1 bird

  5. Duration between 5-240 mins

Overall Notes

  1. Results are sensitive to sample selection criteria (num cities, number days pre/post, home, lockdown date)

  2. We select cities first, and then users. This gives us the same users in each pre/post period (in 2020) with the caveat that users mobility is limited to the top X cities.

  3. Diff-in-diff results consistently positive and strong. Event study somewhat unstable depending on lockdown day. Why is DID counterfactual better?

1.1 Birdwatching Activity in All Cities

Summary Stats for 2020 including users who participated in at least 2 days before and after lockdown.

1.2 Birdwatching Activity in Top 4 Cities

1.3 Top 20 Cities

This is the subset of eBird observations meeting the pariticipation criteria in the top 20 Indian cities by population size. Note that not all top 20 cities may be present in eBird.

eBird Cities in Top 20 by Population Density
COUNTY STATE POP_DENSITY
North East Delhi Delhi 36155.2258
Central Delhi Delhi 27729.5238
East Delhi Delhi 27132.4762
Chennai Tamil Nadu 26552.7543
Kolkata West Bengal 24306.4541
Mumbai Suburban Maharashtra 20979.7354
Mumbai Maharashtra 19652.2994
West Delhi Delhi 19563.4077
South Delhi Delhi 11060.4413
South West Delhi Delhi 5446.4561
Bangalore Karnataka 4381.3985
New Delhi Delhi 4057.2571
Haora West Bengal 3306.0866
North 24 Parganas West Bengal 2444.9880
Chandigarh Chandigarh 909.1664
Hyderabad Telangana 706.8919
Puducherry Puducherry 480.7997

1.4 Pre-Post Lockdown Statistics

This table shows aggregate birdwatching activity in the full sample among users who birdwatched on at least 2 days before and after lockdown (March 24, 2020).
All Cities
PREPOST Num. Trips Num. Cities Num. Users Num. Species
Before 3561 180 351 673
After 10788 139 351 625
Top 20
PREPOST Num. Trips Num. Cities Num. Users Num. Species
Before 753 17 74 205
After 2343 15 74 236

1.5 Trip Statistics

This table shows trip-level statistics before and after lockdown.

All Cities
PREPOST Trip Length Mean Species Richness Median Species Richness
Before 24.16007 12.07638 10
After 22.63969 12.37671 11
Top 20
PREPOST Trip Length Mean Species Richness Median Species Richness
Before 19.86587 10.56574 9
After 22.57192 12.28937 11

1.6 Marginal Species by city

Marginal species are species observed after lockdown which were not observed before lockdown. To implement: in each city, obtain list of species observed (across all users) in before and after lockdown. Extract species in “after” list not in “before” list, and collect in a data frame. If fewer species after, city will not be in final list.

COMMON.NAME SCIENTIFIC.NAME COUNTY
white egret sp. Ardea/Egretta/Bubulcus sp. Kolkata
falcon sp. Falco sp. Kolkata
swift sp. Apodidae sp. Kolkata
Gray-headed Swamphen Porphyrio poliocephalus Kolkata
Rufous Woodpecker Micropternus brachyurus Kolkata
Fulvous-breasted Woodpecker Dendrocopos macei Kolkata
Scaly-breasted Munia Lonchura punctulata Kolkata
Little Egret Egretta garzetta Kolkata
Paddyfield Pipit Anthus rufulus Kolkata
Asian Openbill Anastomus oscitans Kolkata
Zitting Cisticola Cisticola juncidis Kolkata
Spotted Owlet Athene brama Kolkata
Oriental Honey-buzzard Pernis ptilorhynchus Kolkata
Eurasian Moorhen Gallinula chloropus Kolkata
Red-breasted Parakeet Psittacula alexandri Kolkata
House Crow Corvus splendens West Delhi
Laughing Dove Streptopelia senegalensis West Delhi
Indian White-eye Zosterops palpebrosus West Delhi
Common Myna Acridotheres tristis West Delhi
Rose-ringed Parakeet Psittacula krameri West Delhi
Asian Koel Eudynamys scolopaceus West Delhi
Jungle Babbler Turdoides striata West Delhi
Alexandrine Parakeet Psittacula eupatria West Delhi
prinia sp. Prinia sp. West Delhi
Black Drongo Dicrurus macrocercus West Delhi
Indian Silverbill Euodice malabarica Bangalore
Yellow-eyed Babbler Chrysomma sinense Bangalore
swift sp. Apodidae sp. Bangalore
ibis sp. Threskiornithidae sp. (ibis sp.) Bangalore
parakeet sp. Psittaciformes sp. (parakeet sp.) Bangalore
Greater Spotted Eagle Clanga clanga Bangalore
Ashy Woodswallow Artamus fuscus Bangalore
Pied Kingfisher Ceryle rudis Bangalore
Eurasian Spoonbill Platalea leucorodia Bangalore
bird sp. Aves sp. Bangalore
Lonchura sp. Lonchura sp. Bangalore
stork sp. Ciconiidae sp. Bangalore
cormorant sp. Phalacrocoracidae sp. Bangalore
Oriental Honey-buzzard Pernis ptilorhynchus Bangalore
Garganey Spatula querquedula Bangalore
Black-rumped Flameback Dinopium benghalense Bangalore
White-naped Woodpecker Chrysocolaptes festivus Bangalore
Blue-throated Flycatcher Cyornis rubeculoides Bangalore
bee-eater sp. Merops sp. Bangalore
prinia sp. Prinia sp. Bangalore
Red-naped Ibis Pseudibis papillosa Bangalore
Blue-faced Malkoha Phaenicophaeus viridirostris Bangalore
flowerpecker sp. Prionochilus/Dicaeum sp. Bangalore
eagle sp. Accipitridae sp. (eagle sp.) Bangalore
duck sp. Anatinae sp. Bangalore
Blyth’s Pipit Anthus godlewskii Bangalore
Eurasian Coot Fulica atra Bangalore
Indian Nightjar Caprimulgus asiaticus Bangalore
Black-naped Monarch Hypothymis azurea Bangalore
Indian Pitta Pitta brachyura Bangalore
Indian Blue Robin Larvivora brunnea Bangalore
Yellow Bittern Ixobrychus sinensis Bangalore
Black/Ashy Drongo Dicrurus macrocercus/leucophaeus Bangalore
Common Rosefinch Carpodacus erythrinus South Delhi
Rosy Starling Pastor roseus South Delhi
Phylloscopus sp. Phylloscopus sp. South Delhi
Sulphur-bellied Warbler Phylloscopus griseolus South Delhi
Little Swift Apus affinis South Delhi
Red-breasted Flycatcher Ficedula parva South Delhi
Lesser Whitethroat Sylvia curruca South Delhi
Greenish Warbler Phylloscopus trochiloides South Delhi
Cattle Egret Bubulcus ibis South Delhi
Yellow-crowned Woodpecker Leiopicus mahrattensis South Delhi
crow sp. Corvus sp. (crow sp.) South Delhi
parakeet sp. Psittaciformes sp. (parakeet sp.) South Delhi
Large Gray Babbler Turdoides malcolmi South Delhi
Indian Robin Copsychus fulicatus South Delhi
House Sparrow Passer domesticus South Delhi
Indian Silverbill Euodice malabarica Mumbai
Rosy Starling Pastor roseus Mumbai
Jungle Babbler Turdoides striata Mumbai
Phylloscopus sp. Phylloscopus sp. Mumbai
Little Stint Calidris minuta Mumbai
Shikra Accipiter badius Mumbai
Asian Openbill Anastomus oscitans Mumbai
Peregrine Falcon Falco peregrinus Mumbai
Purple Sunbird Cinnyris asiaticus Mumbai
Indian Cormorant Phalacrocorax fuscicollis Mumbai
wagtail sp. Motacilla sp. Mumbai
Brahminy Kite Haliastur indus Mumbai
white egret sp. Ardea/Egretta/Bubulcus sp. Mumbai
swift sp. Apodidae sp. Mumbai
Glossy Ibis Plegadis falcinellus Mumbai
Spotted Owlet Athene brama Mumbai
Bank Myna Acridotheres ginginianus Mumbai
ibis sp. Threskiornithidae sp. (ibis sp.) Mumbai
Little Swift Apus affinis North 24 Parganas
Common Iora Aegithina tiphia North 24 Parganas
Lesser Whistling-Duck Dendrocygna javanica North 24 Parganas
Ashy Woodswallow Artamus fuscus North 24 Parganas
Great Egret Ardea alba North 24 Parganas
Asian Koel Eudynamys scolopaceus Chandigarh
Indian Gray Hornbill Ocyceros birostris Chandigarh
Black-rumped Flameback Dinopium benghalense Chandigarh
Yellow-footed Green-Pigeon Treron phoenicopterus Chandigarh
Red Junglefowl Gallus gallus Chandigarh
Laughing Dove Streptopelia senegalensis Chandigarh
Asian Palm-Swift Cypsiurus balasiensis Mumbai Suburban
Indian Golden Oriole Oriolus kundoo Mumbai Suburban
Indian Robin Copsychus fulicatus Mumbai Suburban
Red-vented Bulbul Pycnonotus cafer Mumbai Suburban
Thick-billed Flowerpecker Dicaeum agile Mumbai Suburban
Laughing Dove Streptopelia senegalensis Mumbai Suburban
Gray/Purple Heron Ardea cinerea/purpurea Chennai
drongo sp. Dicrurus sp. Chennai
Black/Ashy Drongo Dicrurus macrocercus/leucophaeus Chennai
Spotted Dove Streptopelia chinensis Chennai
Great Cormorant Phalacrocorax carbo Chennai
crow sp. Corvus sp. (crow sp.) Chennai
sunbird sp. Nectariniidae sp. (sunbird sp.) Chennai
Common Tern Sterna hirundo Chennai
owl sp. Strigiformes sp. Chennai
Orange-headed Thrush Geokichla citrina Chennai
Red-whiskered Bulbul Pycnonotus jocosus Chennai
Plain Prinia Prinia inornata Chennai
Indian Silverbill Euodice malabarica Chennai
tern sp. Sterninae sp. Chennai
Western Yellow Wagtail Motacilla flava Chennai
Pied Kingfisher Ceryle rudis Chennai
Asian Openbill Anastomus oscitans Chennai
Ashy Prinia Prinia socialis Chennai
Asian Pied Starling Gracupica contra Chennai
Black Bittern Ixobrychus flavicollis Chennai
Little Swift Apus affinis Chennai
Rosy Starling Pastor roseus South West Delhi
Indian Golden Oriole Oriolus kundoo South West Delhi
old world warbler sp. Passeriformes sp. (Old World warbler sp.) South West Delhi
duck sp. Anatinae sp. South West Delhi
Common Chiffchaff Phylloscopus collybita South West Delhi
Little Swift Apus affinis South West Delhi
Long-tailed Shrike Lanius schach South West Delhi
Eurasian Hoopoe Upupa epops South West Delhi
Egyptian Vulture Neophron percnopterus South West Delhi
Oriental Honey-buzzard Pernis ptilorhynchus South West Delhi
Booted Eagle Hieraaetus pennatus South West Delhi
drongo sp. Dicrurus sp. South West Delhi
Gray Heron Ardea cinerea South West Delhi
Great Cormorant Phalacrocorax carbo South West Delhi
Short-toed Snake-Eagle Circaetus gallicus South West Delhi
Blyth’s Reed Warbler Acrocephalus dumetorum South West Delhi
Brown Rock Chat Oenanthe fusca South West Delhi
Rufous Treepie Dendrocitta vagabunda East Delhi
Indian Robin Copsychus fulicatus East Delhi
Red-whiskered Bulbul Pycnonotus jocosus East Delhi
White Wagtail Motacilla alba East Delhi
Green Bee-eater Merops orientalis East Delhi
Striated Babbler Turdoides earlei East Delhi
Purple Heron Ardea purpurea East Delhi
Indian Pond-Heron Ardeola grayii East Delhi
Greater Coucal Centropus sinensis East Delhi
Hume’s Warbler Phylloscopus humei East Delhi
Indian Spot-billed Duck Anas poecilorhyncha East Delhi
Indian Peafowl Pavo cristatus East Delhi
ibis sp. Threskiornithidae sp. (ibis sp.) East Delhi
Woolly-necked Stork Ciconia episcopus East Delhi
White-throated Kingfisher Halcyon smyrnensis East Delhi
Black-rumped Flameback Dinopium benghalense East Delhi
Little Egret Egretta garzetta East Delhi
Shikra Accipiter badius East Delhi
passerine sp. Passeriformes sp. East Delhi
Indian Cormorant Phalacrocorax fuscicollis East Delhi
swift sp. Apodidae sp. East Delhi
Green Sandpiper Tringa ochropus East Delhi
Indian Golden Oriole Oriolus kundoo East Delhi
Little Swift Apus affinis East Delhi
Indian Spotted Eagle Clanga hastata East Delhi
Egyptian Vulture Neophron percnopterus East Delhi
Great Cormorant Phalacrocorax carbo East Delhi
Gray Heron Ardea cinerea East Delhi
Red-breasted Flycatcher Ficedula parva East Delhi
Indian Gray Hornbill Ocyceros birostris East Delhi
Lesser Whitethroat Sylvia curruca East Delhi
Coppersmith Barbet Psilopogon haemacephalus North East Delhi
Rose-ringed Parakeet Psittacula krameri North East Delhi
Asian Koel Eudynamys scolopaceus North East Delhi
Large Gray Babbler Turdoides malcolmi North East Delhi
Brown-headed Barbet Psilopogon zeylanicus North East Delhi
Rock Pigeon Columba livia North East Delhi
Gray Heron Ardea cinerea Puducherry
Barn Owl Tyto alba Puducherry
sunbird sp. Nectariniidae sp. (sunbird sp.) Puducherry
Indian Thick-knee Burhinus indicus Puducherry
Indian Golden Oriole Oriolus kundoo Puducherry
Black-headed Ibis Threskiornis melanocephalus Puducherry
Painted Stork Mycteria leucocephala Puducherry
passerine sp. Passeriformes sp. Puducherry
Green Bee-eater Merops orientalis Puducherry
Red-necked Falcon Falco chicquera Puducherry
White-browed Wagtail Motacilla maderaspatensis Puducherry
Intermediate Egret Ardea intermedia Puducherry
Eurasian Spoonbill Platalea leucorodia Puducherry
white egret sp. Ardea/Egretta/Bubulcus sp. Puducherry
Lonchura sp. Lonchura sp. Puducherry
duck sp. Anatinae sp. Puducherry
Great Egret Ardea alba Puducherry
heron sp. Ardeidae sp. Puducherry
harrier sp. Circus sp. Puducherry
Garganey Spatula querquedula Puducherry
Clamorous Reed Warbler Acrocephalus stentoreus Puducherry
Pied Bushchat Saxicola caprata Puducherry
Rosy Starling Pastor roseus Puducherry
Black Kite Milvus migrans Puducherry
Black-winged Kite Elanus caeruleus Puducherry
Gray-headed Swamphen Porphyrio poliocephalus Puducherry
wagtail sp. Motacilla sp. Puducherry
Indian Robin Copsychus fulicatus Puducherry
Pin-tailed Snipe Gallinago stenura Puducherry
Indian Roller Coracias benghalensis Puducherry
Common Kingfisher Alcedo atthis Puducherry
Little Egret Egretta garzetta Puducherry
Asian Openbill Anastomus oscitans Puducherry
swallow sp. Hirundinidae sp. Puducherry
diurnal raptor sp. Accipitriformes/Falconiformes sp. Puducherry
tern sp. Sterninae sp. Puducherry
Wood Sandpiper Tringa glareola Puducherry
Indian Cormorant Phalacrocorax fuscicollis Puducherry
snipe sp. Gallinago sp. Puducherry
Paddyfield Pipit Anthus rufulus Puducherry
Plain Prinia Prinia inornata Puducherry
Oriental Darter Anhinga melanogaster Puducherry
Tickell’s Blue Flycatcher Cyornis tickelliae Hyderabad
Thick-billed Flowerpecker Dicaeum agile Hyderabad
Large-billed Crow Corvus macrorhynchos Hyderabad
swallow sp. Hirundinidae sp. Hyderabad
Rufous Treepie Dendrocitta vagabunda Hyderabad
Cattle Egret Bubulcus ibis Hyderabad
Indian Peafowl Pavo cristatus Hyderabad
Thick-billed/Pale-billed Flowerpecker Dicaeum agile/erythrorhynchos Hyderabad
Barn Swallow Hirundo rustica Hyderabad
Indian Gray Hornbill Ocyceros birostris Hyderabad
White-browed Wagtail Motacilla maderaspatensis Hyderabad
Gray-bellied Cuckoo Cacomantis passerinus Hyderabad
Glossy Ibis Plegadis falcinellus Hyderabad
Dusky Crag-Martin Ptyonoprogne concolor Hyderabad
Rosy Starling Pastor roseus Hyderabad
River Tern Sterna aurantia Hyderabad
parakeet sp. Psittaciformes sp. (parakeet sp.) Hyderabad
Indian Robin Copsychus fulicatus Hyderabad
Eurasian Kestrel Falco tinnunculus Hyderabad
Little Egret Egretta garzetta Hyderabad
diurnal raptor sp. Accipitriformes/Falconiformes sp. Hyderabad
Indian Pond-Heron Ardeola grayii Hyderabad
Western Yellow Wagtail Motacilla flava Hyderabad
Gray Wagtail Motacilla cinerea Hyderabad
Indian Pond-Heron Ardeola grayii Haora
Jungle Babbler Turdoides striata Haora
Jungle Myna Acridotheres fuscus Haora
Blue-throated Flycatcher Cyornis rubeculoides Haora
Barn Swallow Hirundo rustica Haora
Large-billed Leaf Warbler Phylloscopus magnirostris Haora
Green-crowned Warbler Phylloscopus burkii Haora
Blyth’s Reed Warbler Acrocephalus dumetorum Haora
Intermediate Egret Ardea intermedia Haora
Large-billed Crow Corvus macrorhynchos Haora
Eurasian Collared-Dove Streptopelia decaocto Haora
Asian Palm-Swift Cypsiurus balasiensis Haora
Purple-rumped Sunbird Leptocoma zeylonica Haora
Black-crowned Night-Heron Nycticorax nycticorax Haora
Asian Brown Flycatcher Muscicapa dauurica Haora
Cattle Egret Bubulcus ibis Haora
Greenish Warbler Phylloscopus trochiloides Haora
Greater Coucal Centropus sinensis Haora

2 Event Study (March 24 Lockdown)

We estimate:

\[ SR_{ijtd} = \sum_{e=-24, e\neq0}^{24} 1(t-LD=e)\beta_{e} + X_{ijdt} + \gamma_{t} + \mu_{d} + \epsilon_{ijtd}\] where \(SR_{ijtd}\) is species richness observed by user i on trip j on date t in district d. Each coefficient \(\beta_{e}\) captures species richness relative to the day of lockdown (LD). In the preferred specification, LD = March 24, 2020 and this date is normalized to zero and omitted so that it describes the reference period. If the timing of lockdown is exogenous to pre-period outcomes, then \(\beta_{e}\) should be zero for all \(e<0\). \(\gamma_{t}\) are a set of temporal controls and include date fixed effects and hour fixed effects. \(\mu_{d}\) are city fixed effects. \(X_{ijdt}\) is a vector of controls and includes: duration of trip and user \(i\)’s experience, measured as the number of trips he/she has taken since January 2019.

Notes:

  1. We see action around pilot lockdown, not as much around official lockdown. Suggests people responded to the former.

  2. We start seeing increases in species diversity post-lockdown when we narrow in on urban environments. As we increase allowable cities, this adds population-sparse places so the effect is dampned.

  3. Larger increases in post-lockdown species diversity as we increase the participation constraint (e.g. 10 days before/after curfew)

3 Event Study (March 22 Lockdown)

3.1 Species Distributions (Bangalore Only)

data: number of times each user sees each species before and after lockdown. interpretation: proportion of user base seeing different frequencies of species.

4 Difference-in-Difference (PRELIMINARY)

In this specification, we aim to estimate the difference in species richness per trip before and after lockdown, compared to same difference in 2019. In other words, we subtract the change in the pre-post period of 2019 (the counterfactual) from the 2020 lockdown effect to remove other determinants of species richness that are changing during the window.

To do this, we first select 2020 users with activity in at least 2 days before and after lockdown. Then we add all users from 2019 for the same days. These are different users but share similar characteristics.

Formally, we specify the following standard DID regression:

\[ SR_{ijdt} = \beta_{1} [Treatment_{t} \times Post_{t}] + \beta_{2} [Treatment_{t}] + \beta_{3}[Post_{t}] + X_{ijdt} + \mu_{d} + \gamma_{t} + \epsilon_{ijdt} \]

Where \(Treatment\) is a dummy for the year 2020 and \(Post\) is a dummy equal to one for observations after lockdown. \(\beta_{1}\) is the coefficient of interest and describes the change in species richness before and after March 19 in 2020 compared to the same difference in 2019. \(\beta_{2}\) describes the difference in the “before” groups (pre-intervention). \(\beta_{3}\) captures the time trend in the control (2019) group. \(X_{ijdt}\) is a vector of controls including trip duration. \(\mu_{d}\) is a set of city fixed effects and \(\gamma_{t}\) is a set of temporal controls including date and hour fixed effects.

Diff-in-Diff Estimates (Top 20 cities)
Mar 24 Lockdown Mar 22 Lockdown
Treat x Post 2.291*** 2.500***
(0.373) (0.376)
Duration 0.106*** 0.137***
(0.004) (0.005)
Post -1.611*** -1.264***
(0.405) (0.385)
Treatment -11.520*** -9.608**
(4.156) (3.893)
Num.Obs. 4131 3870
R2 0.293 0.350
Adj.R2 0.289 0.347
AIC 24905.3 23124.3
BIC 25057.1 23274.6
Log.Lik. -12428.653 -11538.158
* p < 0.1, ** p < 0.05, *** p < 0.01